1. Field of the Invention
This invention relates to the mercerization of textiles. More particularly, this invention relates to mercerizing compositions containing wetting agents comprising polycarboxylic acids or salts thereof and nonionic surfactants.
2. The Prior Art
Mercerizing, mainly carried out on cotton, is to improve luster, smoothness of fabric, dye affinity, stabilization, tensile strength and chemical reactivity. The most obvious and most important reason for using bath assistants is to insure proper and prompt wetting of the caustic on the fibers. Other advantages are that bath assistants penetrate the fibers, and speed up the reaction rate of the caustic with the cellulose, and make removal of the caustic easier when mercerization is complete. The process of mercerizing is named after John Mercer, and a description of Mercer's process is set forth in U.S. Pat. No. 8,303 of 1851. Even in Mercer's early work, the need for thorough wetting of the material to be treated was recognized.
The majority of practical mercerizations are carried out using caustic concentrations between 21% and 25%, but caustic strengths ranging from about 14% to 28% may be used. In conjunction with the strong caustic solution, it is generally desirable to use a wetting agent. The wetting agent dissolved in the caustic increases tremendously its penetrating power and helps to effect rapid and even wetting of the cotton with the caustic. Rapid, uniform, and efficient mercerization of the cotton is thereby made possible.
Most wetting agents cannot be used in the mercerizing process as they are not sufficiently soluble in the strongly caustic solutions. Wetting agents have been generally either of two basic types: phenolic-type compounds, such as cresylic acids, or higher alcohols, glycol ethers and sulfonated hydrocarbons. Numerous other such wetting agents have been suggested, such as nitric acid-treated unsaturated fatty acids, as disclosed in U.S. Pat. No. 2,188,287 to Munz.
In general, wetting agents for mercerizing compositions are employed at approximately 1% concentration, based on the weight of the mercerizing caustic solution. The amount of a good penetrant required for the maximum effect rarely exceeds 2%. Some of the wetting agents used in the prior art have high wetting powers, but usually only over a rather narrow range of caustic concentrations. Other penetrants can be used over a wider range of caustic concentrations, but they have poorer wetting powers.
An object of this invention is to provide an aqueous alkaline solution of mercerizing strength having improved wetting and penetrating properties. Another object of this invention is to provide an improved wetting composition for mercerizing solutions. A further object of this invention is to provide mercerizing solutions for the treatment of textile materials. A more specific object of this invention is to provide mercerizing solutions containing wetting agents comprising certain polycarboxylic acids or salts thereof in combination with nonionic surfactants. Yet another object of this invention is to provide mercerizing solutions containing wetting agents comprising normally alkaline-insoluble nonionic surfactants in combination with polycarboxylic acids. Still another object of this invention is to produce alkaline solutions highly efficient for the mercerization of cotton materials. Other objects, features and advantages of this invention will be evident from the following detailed description of the invention.